ELECTRO-OPTIC WAVEGUIDE DEVICE

摘要

An electro-optic waveguide device (10) comprises an assembly of waveguides (30) connected to a common light input region (41) and forming a common far field diffraction pattern (44). The device (10) comprises an n<+> GaAs substrate (14) bearing a waveguide lower cladding layer (16) of n<+> Ga0.9Al0.1As, which is in turn surmounted by a waveguide core layer (18) of n<-> GaAs. The layer (18) has grooves (20) defining the waveguides (30), each of which has a respective Schottky contact (32). Each contact (32) is biased negative with respect to the substrate (14), which reverse biases the respective Schottky diode waveguide structure. The waveguide core layer (18) has electro-optic properties, and its refractive index varies with electric field. The phase of light emerging from each waveguide is therefore independently variable by means of its applied bias voltage. The waveguides (30) are arranged to provide output confined very largely to lowest order spatial modes, so that they produce a single far field diffraction pattern (44). Varying the set of bias voltages applied to the waveguides (30) produces output phase variation which changes the position of the diffraction pattern principal maximum (46) to produce beam steering.